Pseudoroseicyclus aestuarii gen. nov., sp nov., isolated from a tidal flat

A Gram-stain-negative, non-motile, aerobic and coccoid, ovoid or rod-shaped bacterial strain, designated DB-4(T), was isolated from a tidal flat of the Yellow Sea, South Korea. Strain DB-4(T) grew optimally at 30 degrees C, at pH 7.0-8.0 and in the presence of approximately 1.0-2.0% (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain DB-4(T) clustered with the type strain of Roseicyclus mahoneyensis, showing sequence similarity of 94.8 %. It exhibited sequence similarity values of 95.6-96.1 % to the type strains of Loktanella soesokkakensis, Loktanella hongkongensis, Loktanella variabilis, Loktanella aestuariicola and Loktanella cinnabarina. Strain DB-4(T) contained Q-10 as the predominant ubiquinone and C-18:1 omega 7c and cyclo C-19:0 omega 8c as the major fatty acids. The major polar lipids of strain DB-4(T) were phosphatidylcholine, phosphatidylglycerol and one unidentified aminolipid. The fatty acid and polar lipid profiles of strain DB-4(T) were distinguished from those of the type strains of R. mahoneyensis and some phylogenetically related Loktanella species. The DNA G+C content of strain DB-4(T) was 69.2 mol%. On the basis of the phylogenetic, chemotaxonomic and other phenotypic properties, strain DB-4(T) is considered to represent a novel species of a new genus within the family Rhodobacteraceae, for which the name Pseudoroseicyclus aestuarii gen. nov., sp. nov. is proposed. The type strain of Pseudoroseicyclus aestuarii is DB-4(T) (=KCTC 52038(T)=CECT 9025(T)).